Drive with caution — fix soon.
P0120 points to a problem in the throttle or accelerator pedal position sensor 'A' circuit. This sensor tells the computer how far the throttle or pedal is pressed. Faults often come from a worn sensor, wiring problems, or a dirty throttle body, and can cause poor or erratic acceleration.
$100 – $500
Varies by vehicle and root cause.
You can sometimes, but acceleration may be erratic or limited by limp mode. If the car feels unsafe or unpredictable, avoid driving until it's checked.
Usually $100 to $500. A sensor or cleaning is on the lower end, while a full throttle body replacement costs more.
It's moderate. The main risk is unpredictable acceleration or sudden power loss, which is why it's wise to fix it promptly.
Limp mode is a protective state where the computer limits power to keep you safe when it can't trust the throttle signal.